Journal of the Department of Agriculture, Journal of the Department of Agriculture, Western Australia, Series 3 Western Australia, Series 3
Volume 1
Number 5 September-October, 1952 Article 17
9-1952
Insect pest - aphides Insect pest - aphides
C F.H Jenkins
Department of Agriculture
Follow this and additional works at: https://library.dpird.wa.gov.au/journal_agriculture3 Part of the Entomology Commons
Recommended Citation Recommended Citation
Jenkins, C F.H (1952) "Insect pest - aphides," Journal of the Department of Agriculture, Western Australia, Series 3: Vol. 1: No. 5, Article 17.
Available at: https://library.dpird.wa.gov.au/journal_agriculture3/vol1/iss5/17
This article is brought to you for free and open access by the Agriculture at Digital Library. It has been accepted for inclusion in Journal of the Department of Agriculture, Western Australia, Series 3 by an authorized administrator of Digital Library. For more information, please contact [email protected].
INSEC
£££) ^ummaxmb
APHIDES
T
HE members of the aphis family are remarkable creatures both in structure and habits. They are practically world-wide in their distribution and despite their small size and apparent fragility they thrive under a wide variety of conditions and are among the most prolific breeders in the animal kingdom.All the pest species in Australia have been introduced from other p a r t s of the world, and there are only a few rare forms actually native to this continent.
The introduced species, however, have thrived so well t h a t they can be counted among the most serious pests with which the gardener and horticulturist have to contend.
Although one species of aphis will often attack quite a wide variety of hosts, generally a single species or group of plants is favoured, t h u s t h e different species are known as cotton aphis
{Aphis gossypii Glov.); cabbage aphis (Brevicoryne brassicae (L.) ); green peach aphis (Myzus persicae (Sulz.) );
rose aphis (Macrosiphum rosae (L.) ) ; strawberry aphis (Capitophorus fra- gariae (Theob.) ); black citrus aphis
(Toxoptera aurantii (Boy) ); according to the particular plant usually attacked.
On account of their delicate structure aphides do not thrive under extreme conditions of h e a t or cold, neither do they like heavy rain. This accounts for the fact t h a t in most districts it is mainly in the spring a n d a u t u m n t h a t heavy aphis plagues appear. No one can
observe the occurrence of a severe aphis infestation without marvelling a t the astounding rapidity with which the creatures reproduce. This rapid rate of reproduction renders t h e aphis a p a r - ticularly difficult insect to combat a n d means t h a t control measures must be very thoroughly applied if rapid r e - infestations are not to occur.
GENERAL DESCRIPTION Although differing in size a n d colour according to species, aphides, often known as plant lice, can be easily recog- nised by their soft delicate structure and other characteristics. They are sluggish in their movements, have r a t h e r long legs, and are usually found clustered on the host plants. The wings when present are clear. The abdomen is usually rather swollen a n d often carries a pair of horns or cornicles from which a sweet honey-dew much prized by a n t s is excreted.
The mouth parts are produced into a long thin sucking tube, r a t h e r like t h e proboscis of a mosquito, and by m e a n s of this t h i n tube the plant tissue is pierced and the sap imbibed.
661
CONTROL
Blowfly Strike
USE
B.K.B D.D.T
B L O W F L Y D R E S S I N G
With every succeeding season Sheep Farmers And that there is only one Blowfly Dressing to use
—David Grays B.K.B.-D.D.T.
This efficient dressing scores over all others, because in rapidly killing the maggots it not only prevents them from crawling on to near-by areas and re-establishing themselves there, but it so affects them that even if they are able to drop off the sheep they cannot complete their development into flies.
Before using B.K.B.-D.D.T. shear the struck area of the animal to ensure that the full extent of the strike is exposed, and pour on sufficient of the Dressing to saturate the whole area thoroughly; the most satisfactory method to ensure thorough penetration is by lightly dabbing in B.K.B.-D.D.T. with the hand or brush.
David Grays Blowfly Dressing is non-irritant and contains D.D.T. in sufficient strength to safeguard the sheep against restrike and is absolutely 100 per cent.
reliable to kill all flies coming in contact with the dressed animals.
Manufactured by the Chemical
Division of —
avitf ^ i r c y s
DAVID GRAY & CO. LTD., 10 RAILWAY PDE., WEST PERTH
Please mention the "Journal of Agriculture, W.A.," when writing to advertisers
This method of feed- ing should be carefully noted for it is a know- ledge of an insect's feed- ing habits and mechan- ism that is most essential in determining control measures.
LIFE HISTORY In order to understand how the remarkable rate of reproduction is accom- plished it is necessary to have a detailed know- ledge of the general life history of the aphis. After examining a cluster of aphides on a rose or cab- bage leaf, one will notice that all the insects are not identical. Some are larger than others, some are winged and some are wingless.
The large wingless ones are known as stem- mothers. They are females capable of giv- ing rise to living young without having previ- ously been fertilised. The power to reproduce in this manner is known as parthenogenesis. The young from these par- thenogenetic stem-moth- ers grow rapidly and in a few days can in turn pro- duce more living young.
Every now and then, winged females are de- veloped, and have the
same unusual reproductive powers as their wingless parents. These fly to other plants and so spread the infesta- tion.
In cold countries, as winter ap- proaches, male and female aphides are developed, and fertilised eggs are laid on the host plants. These eggs last over the winter and give rise to stem- mothers next spring.
Green Peach Aphis.—Enlarged drawings showing: 1—Winged female (spring form). 2—Wingless female. 3—Nymph or immature winged female.
After E. H. Zeck.
In Western Australia it is doubtful whether the weather is ever severe enough to bring about egg-laying, and the insects carry over from one season to another by means of the few females which survive in sheltered spots.
The life history of many aphides in Europe is complicated by the inclusion of alternate host plants into the cycle, or by a migration of the population to a
663
s u b t e r r a n e a n life on t h e roots. Two local species the black peach aphis (Anur- aphis persicae-niger (Smith) ) and the woolly aphis (Eriosoma lanigerum (Housm.) ) have root-infesting forms but t h e relatively simple life history of most Western Australian aphides can be a t t r i b u t e d to t h e mild climate of this S t a t e .
Colonies of aphides on cabbage leaf.
—Pnoto., U.S. Dept. of Agriculture
CONTROL
Due to t h e fact t h a t t h e aphis is a sap-sucking insect and t h a t it does not actually eat t h e foliage, ordinary pois- onous sprays a n d dusts are useless as
controls. On account of t h e insect's soft a n d delicate structure, however, contact insecticides are very effective.
Sprays.—The chemical most widely used against aphides is nicotine, usually sold under t h e n a m e of Nicotine Sul- p h a t e or "Black Leaf 40." In using nicotine sprays it is essential to add a spreader and activator such as soap or white spraying oil and to apply t h e spray a t a high pressure. Nicotine will give the best results when used on a bright sunny day.
The formula recommended for general use is given below. The quantities shown in brackets are those which may be conveniently used by backyard gar- deners or others who only require small quantities of t h e spraying solution.
Nicotine Sul-
phate . . . . l i pints (2 teaspoonfuls) White Spray-
ing Oil 1 gallon (3 tablespoonfuls) Water loo gallons (1 gallon)
S o aP 4 pounds (loz.) may be used
instead of white spraying oil.
When citrus and other hardy trees are requiring t r e a t m e n t the White Oil strength may be increased from 1:100 to 1:40. Such a concentration will also prove effective against most scale I n - sects found infesting oranges and lemons.
Dusts.—Where it is impracticable to spray, dusts containing nicotine a n d derris have been used with good results.
Two mixtures once very popular were:—
(1) Nicotine Sulphate .... 1 part Slaked Lime 16 p a r t s (2) Tobacco Dust .... 1 part
Slaked Lime 1 part New Insecticides.—Under this heading may be grouped DDT, Benzene-hexa- chloride (BHC) or Gammexane, HETP or "Hexone" (Hexaethyltetraphosphate), P a r a t h i o n or E.605 ("Folidol" a n d "Phos- phone") and the systemic insecticides.
Of t h e list outlined "Hexone" and P a r a t h i o n are probably the most gen- erally useful against aphis, although all
are effective against some species. Con- centrations of 1 part to 1,600 parts of water have been widely recommend- ed but it is usually desirable to follow the dilution rates recommended by the manufacturers as the amount of active ingredients may vary with different brands.
The use of DDT for aphis control is not to be recommended except under special circumstances as the insecticide kills many useful parasites and may lead to an increase in some scale insects and mites. Where for any reason DDT is de- sired for aphis control, emulsion types are recommended. Several workers have reported them superior to the wettable powders and the concentration suggested is 0.1%.
A combination of insecticides particu- larly useful to market gardeners is a dust consisting of 2% DDT and 2%
BHC. The former satisfactorily con- trols chewing insects such as cabbage caterpillars and the BHC reduces the aphis population.
"Hexone" and Parathion were both deevloped during the war to alleviate a world shortage of nicotine sulphate and have proved most effective substitutes for the tobacco extract. The insecticide group (organic phosphates) to which
"Hexone" and Parathion belong is very toxic to the higher animals and so must be used with great caution. Gloves should be worn when mixing the sprays to prevent any concentrates coming in- to contact with the bare skin. When spraying, precautions should be taken to see that the spray mist is not inhaled and that clothing does not become saturated with spray liquid. Although a very effective contact insecticide,
"Hexone" has little residual effect and the toxicity of the mixture deteriorates rapidly once it is diluted and exposed to the air. Parathion on the other hand has an appreciable residual action and also some of the properties of a sys- temic insecticide. This renders Para- thion the more dangerous of the two preparations and means that it should not be applied to fruits or vegetables later than a month before picking.
Black peach aphides on peach shoot.
—Photo., British Ministry of Agriculture
The systemic insecticides depend for their efficiency on the fact that the materials enter the sap stream and ac- cumulate in the vigorously growing por- tions of the plant. Systemic materials may be sprayed on the foliage or wat- ered around the roots. They are ex- tremely selective in their action and, of course, only affect sap-sucking insects.
This is of great importance as it allows ladybirds a n d wasp parasites to go u n - molested and continue their work of scale a n d aphis control.
Young peach leaves showing the characteristic curling and distortion caused by aphides feeding
on the under-surfaces.
T h e use of "systemics" is still largely in t h e experimental stage. At the present time none is commercially available locally and m a n y of those in use overseas are very dangerous to h u m a n s a n d c a n be used only with
special protective clothing and other precautions.
Biological Control.—There are many excellent examples of the biological con- trol of aphides. Ladybirds feed readily upon most species, and a number of tiny wasps lay their eggs into a n d develop within t h e aphis. The cabbage aphis is one variety largely controlled by a wasp parasite introduced into this State in 1907 by t h e late Mr. George Compere.
The parasitised aphides may be dis- tinguished from t h e healthy insects by their bloated appearance and light colour, a n d later by t h e tiny hole in t h e back from which the wasp h a s emerged.
Cultural Methods.—All weeds likely to harbour aphis should be destroyed and especial a t t e n t i o n given to weeds closely related to the crop being grown. For instance, wild radish and wild t u r n i p will harbour cabbage aphis, and may easily be responsible for s t a r t - ing an outbreak in a commercial crop.
When cutting cabbages and cauli- flowers t h e whole plant should be de- stroyed, so t h a t t h e b u t t is not left to breed further pests- Similarly when any crop is finished t h e old plants should be got rid of as soon as possible, for carelessness in this direction leads to t h e dissemination of diseases and i n - sect pests of all kinds.
*** * • * * • • *•* *•* ••* *•* *•* *•* ••• *•* ••* • * • * * • ••* *•* * • • • • • ••* ••* **• * • • *•* **• *** *** *•* • * • *•* *•* *•* * • • * ^ ••* *•* *•* *** ••* ••* *•• *•• *•* •»* *•• •»• * • • ••• * • • *•* • * • *«* *•* •*• *•* ••* *•* ••• *•* *•* **• *•* ••* *•* *•* *•* *•* *•* ***
•
•
• •
t
•
•
KEEP YOUR JOURNALS
H
ERE at the production end, we are sparing neither expense nor effort in making the "Journal of Agriculture" a publication which will help you in your farming operations.We suggest that the Journal is worth keeping and that a year's issue will make an attractive and useful volume for your library—a volume that is full of sound factual information, attractively presented.
Arrangements have been made for the compilation of a comprehensive index to be incorporated in the December issue—a feature which will greatly enhance the value of the Journal as a work of reference.
• • • » • • • • • • • • • • • » • • • » • • • • • • • • • • » • • • » • • • • • • • • • • • • • • • • • • • • • • , • • • • • • • '
666
